Head assembly and disk device provided with the same

ABSTRACT

According to one embodiment, a head gimbal assembly includes a support plate, a wiring member including a thin metallic plate, an insulating layer and a conductive layer, the wiring member including a tongue portion located on a convex portion of the support plate, a proximal end portion fixed onto the support plate, and a bridge portion bridged between the tongue portion and the proximal end portion and including a inflection point with respect to a height direction of warping, a magnetic head attached to the tongue portion, and a piezoelectric element bonded to the bridge portion at a section between the proximal end portion and the inflection point.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.14/300,732, filed on Jun. 10, 2014, which is based upon and claims thebenefit of priority from Japanese Patent Application No. 2014-031426,filed Feb. 21, 2014; the entire contents of these applications areincorporated herein by reference.

FIELD

Embodiments described herein relate generally to a head gimbal assemblyto be applied to a disk device, and also a disk device provided with thehead gimbal assembly.

BACKGROUND

In recent years, disk devices such as magnetic disk drives and opticaldisk drives have widely been used as external recording devices ofcomputers and image recording devices.

As such a disk device, for example, a magnetic disk drive generallycomprises a magnetic disk provided in a case, a spindle motor whichsupports and rotates the magnetic disk, and a head gimbal assembly (HGA)which supports a magnetic head. The head gimbal assembly includes asuspension attached to a distal end portion of an arm, a wiring member(a flexure or a wiring trace) provided on the suspension and extendingoutwards from the suspension, and a magnetic head supported on thesuspension through a gimbal portion of the wiring member. The wiringmember includes wirings electrically connected to the magnetic head.

In recent years, there is proposed an HGA wherein thin piezoelectricelements (PZT elements) are mounted at a gimbal portion of a wiringmember, and a magnetic head is minutely displaced in a seek direction byexpansion and contraction of the piezoelectric elements. According tothe HGA, operation of the magnetic head can be minutely controlled bycontrolling a voltage to be applied to the piezoelectric elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a hard disk drive (HDD) accordingto a first embodiment;

FIG. 2 is a side view showing a magnetic disk, a suspension and amagnetic head of a head gimbal assembly in the HDD;

FIG. 3 is a plan view of the head gimbal assembly;

FIG. 4 is a perspective view showing the head gimbal assembly;

FIG. 5 is an exploded view showing a load beam, a flexure, piezoelectricelements and the magnetic head of the head gimbal assembly;

FIG. 6 is a plan view of a distal end portion of the head gimbalassembly;

FIG. 7 is a cross-sectional view of a piezoelectric-element mountingportion, taken along line C-C in FIG. 6, with a piezoelectric elementstill not mounted;

FIG. 8 is a cross-sectional view of the piezoelectric-element mountingportion, taken along line C-C in FIG. 6, with the piezoelectric elementmounted;

FIG. 9 is a plan view schematically showing a state of a magnetic headminutely displaced by piezoelectric elements;

FIG. 10 is a view showing a result of driving amounts of magnetic headsper voltage, which are simulated by a finite-element analysis, in thecase where in a head gimbal assembly according to the first embodiment,both end portions of each of piezoelectric elements are fixed and in thecase where in a head gimbal assembly according to a comparative example,both end portions of each of piezoelectric elements are in a floatedstate;

FIG. 11 is a cross-sectional view of a piezoelectric-element mountingportion in a head gimbal assembly according to a second embodiment; and

FIG. 12 is a cross-sectional view of a piezoelectric-element mountingportion in a head gimbal assembly according to a third embodiment.

DETAILED DESCRIPTION

Various embodiments will be described hereinafter with reference to theaccompanying drawings. In general, according to one embodiment, a headgimbal assembly comprises:

a support plate comprising a distal end portion with a convex portion;

a wiring member comprising a thin metallic plate, an insulating layer onthe thin metallic plate and a conductive layer on the insulating layer,to form a plurality of wirings, the wiring member being attached to thesupport plate at the thin metallic plate side, the wiring membercomprising a tongue portion located on the convex portion, a proximalend portion fixed onto the support plate apart from the tongue portion,and a bridge portion bridged between the tongue portion and the proximalend portion, the bridge portion being allowed to be warped from theproximal end portion to the tongue portion in accordance with aprojection height of the convex portion, and including a inflectionpoint with respect to a height direction of warping of the bridgeportion;

a magnetic head attached to the tongue portion and electricallyconnected to the wirings of the wiring member; and

a piezoelectric element bonded to the bridge portion at a sectionbetween the proximal end portion and the inflection point, thepiezoelectric element being configured to expand and contract by anapplied voltage in a longitudinal direction of the wiring member.

A hard disk drive (HDD) according to an embodiment, as a magnetic diskdevice, will be explained with reference to the accompanying drawings.

First Embodiment

FIG. 1 shows an internal structure of an HDD, with a top cover detachedtherefrom, and FIG. 2 schematically shows a magnetic disk and a magnetichead being in a floated (flying) state. As shown in FIG. 1, the HDD isprovided with a housing 10. The housing 10 comprises a base 12 formed inthe shape of a rectangular box which is open on its upper side, and atop cover (not shown) fixed to the base 12 by a plurality of screws tocover an upper opening of the base 12. The base 12 includes arectangular bottom wall 12 a and a side wall 12 b provided upright alonga peripheral edge of the bottom wall 12 a.

In the housing 10 are arranged two magnetic disks 16 as storage mediums,and a spindle motor 18 provided as a driving section which supports androtates the magnetic disks 16. The spindle motor 18 is disposed on thebottom wall 12 a. The magnetic disks 16 are engaged coaxially with a hub(not shown) of the spindle motor 18, clamped by a clamp spring 27, andthereby fixed to the hub. The magnetic disks 16 are supported inparallel with the bottom wall 12 a of the base 12. The magnetic disks 16are rotated at a predetermined speed by the spindle motor 18 in adirection indicated by arrow A.

A plurality of magnetic heads 17 and a head stack assembly (hereinafterreferred to as an HSA) 22 are arranged in the housing 10. The magneticheads 17 are configured to write and read information on and from themagnetic disks 16, and the HSA 22 supports the magnetic heads 17 suchthat they are movable with respect to the magnetic disks 16. In thehousing 10 are arranged a voice coil motor (VCM) 24, a ramp loadmechanism 25, a latch mechanism 26 and a board unit 21. The VCM 24rotates and positions the HSA 22, the ramp load mechanism 25 holds themagnetic heads 17 in unload positions where they are separated from themagnetic disks 16, when the magnetic heads 17 are moved to outermostcircumferential part of the magnetic disks 16, the latch mechanism 26holds the HSA in a retreat position when an impact or the like acts onthe HDD, and the board unit 21 includes a conversion connector, etc. Itshould be noted that the latch mechanism 26 is not necessarily limitedto a mechanical one, and a magnetic latch may be used.

A printed circuit board (not shown) is attached to an outer surface ofthe bottom wall 12 a of the base 12. The printed circuit board controlsoperations of the spindle motor 18, the VCM 24 and the magnetic heads 17through the board unit 21. A circulation filter 23 configured to capturedust caused in the housing 10 by the operations of the movable parts isprovided on the side wall 12 b of the base 12, and is positioned outsidethe magnetic disks 16. Further, a breather filter 15 configured tocapture dust from the air flowing into the housing 10 is provided on theside wall 12 b of the base 12.

As shown in FIG. 1, the HSA 22 comprises a rotatable bearing unit 28,four arms 32 attached to the bearing unit 28 in a stacked state, headgimbal assemblies (hereinafter referred to as HGAs) 30, and spacer rings(not shown) provided between the arms 32 arranged in the stacked state.Each of the arms 32 is formed of, for example, stainless steel, aluminumor the like into an elongate and thin plate-shape. Each arm 32 includesa distal end portion at its extended end side. At the distal endportion, a caulking seating face having a caulking hole (not shown) isformed.

As shown in FIGS. 1 and 2, each of the magnetic disks 16 comprises asubstrate 101 formed of a nonmagnetic substance and in the shape of adisc having a diameter of approximately 2.5 inches (6.35 cm). On bothsurfaces of the substrate 101, soft magnetic layers 102, magneticrecording layers 103 and protection film layers 104 are stacked in thisorder. The soft magnetic layers 102 are provided as underlying layersand formed of material assuming a soft magnetic characteristic.

As shown in FIG. 2, each of the magnetic heads 17 is formed as a flyingtype head, and comprises a slider 31 formed in a substantiallyrectangular parallelepiped shape, and a head section 33 formed in anoutflow end (trailing) side of the slider. Each magnetic head 17 issupported on a distal end portion of a suspension 34 by a gimbal portionof a flexure, which will be described later. Each magnetic head 17 isflied by airflow B which is generated between a surface of the magneticdisk 16 and the slider 31 by rotation of the magnetic disk 16. Thedirection of airflow B is coincident with a rotating direction of themagnetic disk 16. The slider 31 is arranged such that its longitudinaldirection is substantially coincident with the direction of airflow Bwith respect to the surface of the magnetic disk 16.

Next, structures of the HGAs 30 will be explained in detail. FIG. 3 is aplan view of each of the HGAs 30, and FIG. 4 is a perspective view ofeach HGA.

As shown in FIGS. 1, 3 and 4, the HGA 30 comprises the suspension 34extending from the arm 32, and the magnetic head 17 supported on theextended end of the suspension 34.

The suspension 34, which functions as a supporting plate, includes arectangular base plate 42 formed of a metal plate having a thickness ofseveral hundreds of microns, and a load beam 35 formed of a metal platewith a thickness of tens of microns in a shape of an elongate and thinleaf spring. The load beam 35 has a proximal end portion located on adistal end portion of the base plate 42, and is fixed to the base plate42 by welding a plurality of portions of the load beam 35. The proximalend potion of the load beam 35 has a width substantially equal to thatof the base plate 42. An elongate and thin rod-shaped tab 46 is providedat the distal end of the load beam 35 in a protruding manner.

The base plate 42 includes, at a proximal-end portion thereof, acircular opening 42 a, and annular protrusion 43 positioned around theopening 42 a. By fitting the protrusion 43 of the base plate 42 in thecircular caulking hole (not shown) formed in the seating face forcaulking provided on the arm 32, and caulking the protrusion 43, thebase plate 42 is fastened to the distal-end portion of the arm 32. Thedistal end of the base plate 42 may be fixed to the distal end of thearm 32 with swaging.

The HGA 30 comprises a pair of piezoelectric elements (PTZ elements) 50and a flexure (wiring member) 40 formed in the shape of an elongatebelt-shape and configured to transmit a recording signal and areproduction signal for the magnetic head 17 and a drive signal for thepiezoelectric elements 50. As shown in FIGS. 3 and 4, the flexure 40includes a distal end portion 40 aattached to upper surfaces of the loadbeam 35 and the base plate 42, and a posterior-half portion (extensionportion) 40 b extending outwards from a side edge of the base plate 42and along a side edge of the arm 32. Also, the flexure 40 includes aconnecting end portion 40 c which is located at a distal end of theextension portion 40 b, and also which is connected to a main FPC 21 bwhich will be described later.

The distal end portion of the flexure 40, which is located on the distalend portion of the load beam 35, forms the gimbal portion 36. Themagnetic head 17 and piezoelectric elements 50 are mounted on the gimbalportion 36. The magnetic head 17 is fixed onto the gimbal portion 36,and is supported on the load beam 35 through the gimbal portion 36. Thepair of piezoelectric elements (PZT elements) 50 are attached to thegimbal portion 36, and located in the vicinity of the magnetic head 17on the proximal end side of the load beam 35 with respect to themagnetic head 17.

FIG. 5 is an exploded perspective view of the magnetic head, thepiezoelectric elements, the flexure and the load beam of each HGA 30;and FIG. 6 is a plan view of the distal end portion of each HGA 30.

As shown in FIGS. 3 to 6, the flexure 40 comprises a thin metallic plate(lining layer) 44 a formed as a base and also formed of stainless or thelike, an insulating layer 44 b formed on the thin metallic plate 44 a, aconductive layer (wiring pattern) 44 c formed on the insulating layer 44b and constituting a plurality of wirings 45 a, and a protection layer(insulating layer, not shown) covering the conductive layer 44 c. Theflexure 40 constitutes an elongate belt-shaped laminated plate. Theflexure 40 is attached to the surfaces of the load beam 35 and baseplate 42 at the thin metallic plate 44 a side thereof by adhering orlaser welding.

In the gimbal portion 36 of the flexure 40, the thin metallic plate 44 aincludes: a rectangular tongue portion 36 a located at the distal endside; a rectangular proximal end portion 36 b located on the proximalend side, with a space 36 f interposed between the proximal end portion36 b and the tongue portion 36 a; a pair of link portions 36 c extendingfrom the tongue portion 36 a to the proximal end portion 36 b; and apair of island-shaped support portions 36 d located in the space 36 fbetween the tongue portion 36 a and the proximal end portion 3 b. Theproximal end portion 36 b is fixed onto a surface of the load beam 35 byspot welding or the like. A substantially central portion of the tongueportion 36 a is in contact with a dimple (support convex portion) 48projectingly provided at the distal end portion of the load beam 35. Thetongue portion 36 a and the magnetic head 17 fixed onto the tongueportion 36 a can be rocked or rolled about the dimple 48 by elasticdeformation of the link portions 36 c.

At the gimbal portion 36, the insulating layer 44 b and the conductivelayer 44 c of the flexure 40 are formed to branch into two parts, andinclude: proximal end portion 47 a fixed onto the proximal end portion36 b of the thin metallic plate 44 a; a distal end portion 47 b bondedonto the tongue portion 36 a; and a pair of elongate bridge portions 47c extending from the proximal end portion 47 a to the distal end portion47 b and the tongue portion 36 a, and also extending in the longitudinaldirection of the load beam 35. The island-shaped support portions 36 dare fixed to respective middle portions of the bridge portions 47 c.

The magnetic head 17 is fixed to the tongue portion 36 a by an adhesive,with a part of the distal end portion 47 of the flexure 40 interposedbetween the magnetic head 17 and the tongue portion 36 a. The magnetichead 17 is electrically connected to the wirings 45 a through aplurality of connection pads 40 d formed at the distal end portion 47 b.As the pair of piezoelectric elements 50, for example, thin filmpiezoelectric elements formed in the shape of a rectangular plate areapplied. The piezoelectric elements 50 are bonded to the bridge portions47 c by an adhesive or the like, respectively. The piezoelectricelements 50 are arranged such that their longitudinal direction is inparallel to those of the load beam 35 and the bridge portions 47 c.Thus, the pair of piezoelectric elements 50 are arranged side by side inparallel with each other, and located on both sides of the magnetic head17. The piezoelectric elements 50 are electrically connected to thewirings 45 a.

As shown in FIGS. 3 and 4, the wirings 45 a of the flexure 40 includewirings 45 a for transmitting a recording and reproduction signal to themagnetic head 17, which extend to the magnetic head 17, and areconnected to the connection pads 40 d. The connection pads 40 d areelectrically connected to a recording and reproduction element of themagnetic head 17 by solder. Also, the wirings 45 a of the flexure 40include wirings 45 a for transmitting a drive signal to thepiezoelectric elements 50, which extend to the vicinity of thepiezoelectric elements 50, and include extension ends having connectionpads (not shown). The connection pads and the piezoelectric elements 50are electrically connected to each other by solder or a conductiveadhesive agent such as silver paste. It should be noted that the wirings45 a of the flexure 40 extend to a connecting end portion 40 c of theflexure 40 along the flexure 40, and are connected to connection pads 40f provided at the connecting end portion 40 c.

FIG. 7 is a cross-sectional view showing the bridge portion, with apiezoelectric element 50 not still mounted; and FIG. 8 is across-sectional view showing the bridge portion, with the piezoelectricelements 50 mounted.

As shown in FIGS. 6 and 7, the tongue portion 36 a of the flexure 40 islocated on the dimple (convex portion) 48 of the load beam 35, and alsolocated at a higher position than the proximal end portion 47 a of theflexure 40. In a direction perpendicular to a surface of the load beam35, the tongue portion 36 a is located further apart from the load beam35 than the distal end portion 47 b. Thus, the bridge portion 47 cbridged between the proximal end portion 47 a and the tongue portion 36a is naturally and sigmoidally warped from the proximal end portion 47 ato the tongue portion 36 a into a substantially S-shape in accordancewith a projection height of the dimple 48, i.e., in accordance with thedifference between a height of the proximal end portion 47 a and that ofthe tongue portion 36 a in the direction perpendicular to the surface ofthe load beam 35. Thereby, the bridge portion 47 c has a warp inflectionpoint P in a height direction at a substantially central portion of thebridge portion 47 c in a longitudinal direction thereof. That is, thebridge portion 47 c is warped such that a section between the proximalend portion 47 a and the inflection point P is warped in a convexedlyarcuate shape toward the load beam 35, and also a section between theinflection point P and the tongue portion 36 a is warped in a convexedlyarcuate shape in a direction away from the load beam 35.

As shown in FIGS. 6 and 8, the piezoelectric element 50 is bonded by anadhesive agent 51 to a surface of the bridge portion 47 c (which islocated opposite to a surface facing the load beam 35) at the section ofthe bridge portion 47 c which is located between the proximal endportion 47 a and the inflection point P. The support plate 36 d of thethin metallic plate 44 a is fixed to a reverse surface of the bridgeportion 47 c (which faces the load beam 35) in the vicinity of theinflection point P (especially, on a proximal end portion (47 a) sidefrom the inflection point P). In the longitudinal direction of thepiezoelectric element 50, one of end portions of the piezoelectricelement 50 is fixed to the bridge portion 47 c while being partiallystacked on the support portion 36 d, and the other end portion is fixedto the bridge portion 47 c while being partially stacked on the proximalend portion 47 a.

Since the piezoelectric element 50 is provided in the above manner, theboth end portions of the piezoelectric element 50 in the longitudinaldirection thereof can be brought in contact with the bridge portion 47c. Therefore, the both end portions of the piezoelectric element 50 inthe longitudinal direction thereof can be stably and reliably made toadhere to the bridge portion 47 c, and can thus be prevented frompeeling from the bridge portion 47 c. As a result, it is possible torestrict variance between displacement (stroke amount) of thepiezoelectric element 50 and variation of a resonance characteristic ofthe piezoelectric element 50.

When a voltage is applied to the piezoelectric elements 50 through thewirings 45 a, the piezoelectric elements 50 are expanded or contractedin their longitudinal direction. To be more specific, as shown in FIG.9, the piezoelectric elements 50 are extended and contracted in oppositedirections, thereby enabling the tongue portion 36 a of the gimbalportion 36 to be rocked along with the flexure 40, and the magnetic head17 to be displaced in the seeking direction.

As shown in FIG. 1, the HSA 22 includes a support frame extending fromthe bearing unit 28 in a direction away from the arms 32, and thesupport frame includes a voice coil which is embedded therein, and whichforms part of the VCM 24. Each of the magnetic disks 16 is locatedbetween associated two of the HGAs 30, with the HSA 22 mounted in thebase 12. While the HDD is being operated, the magnetic heads 17 of theHGAs 30 face upper and lower surfaces of the magnetic disks 16, and arelocated on both sides of the magnetic disks 16. The voice coil, which isfixed to the support frame, is located between a pair of yokes 37 fixedonto the base 12. The voice coil, the yokes 37 and a magnet (not shown)fixed to one of the yokes 37 constitute the VCM 24.

As shown in FIG. 1, the board unit 21 includes a main body 21 acomprising a flexible printed circuit board. The main body 21 a is fixedto the bottom wall 12 a of the base 12. Electronic components (notshown) such as a conversion connector, etc. are mounted on the main body21 a. A connector (not shown) for connection with the print circuitboard is mounted on a bottom surface of the main body 21 a.

The board unit 21 includes a main flexible print circuit board(hereinafter referred to as a main FPC) 21 b extending from the mainbody 21 a. An extended end of the main FPC 21 b forms a connecting endportion, and is fixed in the vicinity of the bearing unit 28 of the HSA22. The connecting end portion 40 c of the flexure 40 of each HGA 30 ismechanically and electrically connected to the connecting end portion ofthe main FPC 21 b. Thereby, the board unit 21 is electrically connectedto the magnetic heads 17 and the piezoelectric elements 50 by the mainFPC 21 b and the flexures 40.

As shown in FIG. 1, the ramp load mechanism 25 comprises a ramp 70located on the bottom wall 12 of the base 12 and outward of the magneticdisks 16, and tabs 46 (see FIGS. 3 to 5) extending from the distal endsof the suspensions 34. In the case where the HSA 22 is rotated about thebearing unit 28, and the magnetic heads 17 are moved to retreatpositions located outward of the magnetic disks 16, each of the tabs 46is engaged with a ramped surface formed at the ramp 70, and then pulledupwards due to a slant of the ramped surface. As a result, the magneticheads 17 are unloaded form the magnetic disks 16, and held in theretreat positions.

In the HDD and the HGA 30 with the above mentioned structure, thepiezoelectric elements 50 are attached to the bridge portions 47 c ofthe flexures (wiring member) 40, and a voltage is applied to thepiezoelectric elements 50 through the flexures 40, thereby enabling themagnetic head 17 attached to the gimbal portion 36 to be displaced inthe seeking direction. By virtue of this feature, it is possible tominutely control the position of the magnetic head 17 by controlling thevoltage to be applied to the piezoelectric elements 50, and thus improvethe accuracy of positioning of the magnetic head.

Each of the piezoelectric elements 50 is bonded by the adhesive agent 51to a surface of part of the bridge portion 47 c, which is located withina section between the proximal end portion 47 a and the inflection pointP. Thus, the both end portions of the piezoelectric element 50 in thelongitudinal direction can be set in contact the bridge portion 47 c,and be reliably made to adhere to the bridge portion 47 c. As a result,the both end portions are prevented from peeling off the bridge portion47 c. Therefore, it is possible to ensure that the magnetic heads 17 canbe driven without loss of driving amount with respect to displacementamounts (stroke amount) of the piezoelectric elements 50. In addition,by preventing peeling or floating of the piezoelectric elements 50, itis also possible to prevent excitation of unnecessary resonance of thepiezoelectric elements 50, and improve the resonance characteristicsthereof.

FIG. 10 is a view showing a result of driving amounts of magnetic headsper voltage, which are simulated by a finite-element analysis, in thecase where in a head gimbal assembly according to the first embodiment,both end portions of each of piezoelectric elements are fixed and in thecase where in a head gimbal assembly according to a comparative example,both end portions of each of piezoelectric elements are in a floatedstate. From this figure, it can be seen that the driving amount(displacement width) of the magnetic head 17 is 100% in the case wherethe both end portions of each piezoelectric element 50 are properly madeto adhere to the wiring member, and are not floated, as in theembodiment, whereas the driving amount of the magnetic head 17 areapproximately 20% in the case where the both end portions of eachpiezoelectric element are in a floated state; that is, its loss isgreat. In addition, since the degree of the loss depends on the degreeof floating of each piezoelectric element, if adhesion of the both endportions of each piezoelectric element is stably achieved, the magnetichead can be driven without loss of driving amount, and simultaneouslythe variation of its driving amount can be reduced.

Next, HGAs according to another embodiments will be described. Inanother embodiments, elements identical to those in the first embodimentwill be denoted by the same reference numerals and signs, and theirdetailed explanations will be omitted.

Second Embodiment

FIG. 11 is a cross-sectional view showing a piezoelectric element and abridge portion in an HGA 30 according to a second embodiment. Accordingto the second embodiment, a piezoelectric element 50 is curved inadvance such that its curve is coincident with that of a section of abridge portion 47 c, which is located between a proximal end portion 47a and an inflection point P. The piezoelectric element 50 is bonded byan adhesive agent 51 to a surface of the bridge portion 47 c (which islocated opposite to a load beam 35) at the above section located betweenthe proximal end portion 47 a and the inflection point P. Thepiezoelectric element 50 is also kept curved after being mounted.

According to the second embodiment, the curved states of the bridgeportion 47 c and the piezoelectric element 50 are made coincident witheach other, and they can thus be made to further stably adhere to eachother. Furthermore, in the case where the piezoelectric element 50 is athin film piezoelectric element, a given compression stress acts in thepiezoelectric element due to the curve thereof, thus increasing adisplacement constant per voltage. Therefore, according to the secondembodiment, the piezoelectric element can be made to stably adhere tothe bridge portion 47 c, and in addition a higher displacement constantcan be obtained without the need to replace the piezoelectric element toanother one.

Third Embodiment

FIG. 12 is a cross-sectional view showing a piezoelectric element and abridge portion in an HGA 30 according to a third embodiment. Accordingto this embodiment, at least one portion of a bridge portion 47 c issubjected to curving processing, and formed as a bent portion 55 whichis convex toward a load beam 35. The bent portion 55 is provided betweena proximal end portion 47 a of the bridge portion 47 c and an inflectionpoint P. Furthermore, between the proximal end portion 47 a of thebridge portion 47 c and the inflection point P, a piezoelectric element50 is fixed by an adhesive agent 51 in such a way as to bridge the bentportion 55.

As a result, both end portions of the piezoelectric element 50 in alongitudinal direction thereof can be brought in contact with the bridgeportion 47 c, and can also be made to stably and reliably adhere to thebridge portion 47 c.

It should be noted that the location of the bent portion 55 is notlimited to that between the proximal end portion 47 a of the bridgeportion 47 c and the inflection point P; that is, the bent portion 55may be provided at another location. For example, the bent portion 55may be provided at the inflection point P, and the piezoelectric element50 may be bonded to the bridge portions 47 c in such a way as to bridgethe bent portion 55. In this case, the both end portions of thepiezoelectric element 50 in the longitudinal direction thereof can bemade to reliably adhere to the bridge portion 47 c.

In the second and third embodiments, it is possible to prevent peelingor floating of the both end portions of the piezoelectric element, andimprove the displacement width of the magnetic head due to thepiezoelectric elements. Further, it is possible to prevent excitation ofunnecessary resonance of the piezoelectric element, and improve theresonance characteristic thereof.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

In the above embodiments, as the arms of the HSA, plate-shaped armsformed independent of each other are applied. However, the arms of theHSA are not limited to the plate-like arms; that is, the arms may beformed in the shape of so-called E-type block and integral with bearingsleeves. Furthermore, the size of each of the magnetic disks is notlimited to 2.5 inches; that is, magnetic disks each having another sizemay be applied. The number of magnetic disks is not limited to two; thatis, a single magnetic disk or three or more magnetic disks may beapplied. Also, the number of HGAs may be changed in accordance with thenumber of magnetic disks.

What is claimed is:
 1. A suspension assembly comprising: a support platewith a convex portion; a wiring member comprising a metallic plate, aninsulating layer on the metallic plate and a conductive layer on theinsulating layer, to form a plurality of wirings, the wiring memberfurther comprising a support portion located on the convex portion, aproximal end portion fixed onto the support plate, and a bridge portionbridged between the support portion and the proximal end portion, thebridge portion comprising a middle portion between the proximal endportion and the support portion, a first curved portion convex towardthe support plate between the proximal end portion and the middleportion, and a second curved portion convex in a direction opposite tothe support plate between the middle portion and the support portion,the middle portion being at a boundary between the first and secondcurved portions; and a drive element attached to the first curvedportion except for the second curved portion, the drive element beingconfigured to expand and contract according to an applied voltage in alongitudinal direction of the wiring member.
 2. The suspension assemblyof claim 1, wherein the drive element is provided only at the firstcurved portion of the bridge portion.
 3. The suspension assembly ofclaim 1, wherein the metallic plate further comprises an island-shapedportion located between the proximal end portion and the support portionand attached to the bridge portion close to the middle portion.
 4. Thesuspension assembly of claim 3, wherein the drive element is attached tothe bridge portion such that a longitudinal direction of the driveelement is coincident with a longitudinal direction of the bridgeportion, and both end portions of the drive element in the longitudinaldirection thereof are in contact with the wiring member.
 5. Thesuspension assembly of claim 4, wherein one of end portions of the driveelement in the longitudinal direction is fixed to the wiring memberwhile being partially stacked on the island-shaped portion, and theother end portion is fixed to the wiring member while being partiallystacked on the proximal end portion.
 6. The suspension assembly of claim1, wherein the drive element is formed in a curved shape in accordancewith curves of the first curved portion.
 7. A head suspension assemblycomprising: the pension assembly of claim 1; and a magnetic headsupported on the support portion.
 8. The head suspension assembly ofclaim 7, wherein the drive element is provided only at the first curvedportion of the bridge portion.
 9. The head suspension assembly of claim7, wherein the metallic plate further comprises an island-shaped portionlocated between the proximal end portion and the support portion andattached to the bridge portion close to the middle portion.
 10. The headsuspension assembly of claim 9, wherein the drive element is attached tothe bridge portion such that a longitudinal direction of the driveelement is coincident with a longitudinal direction of the bridgeportion, and both end portions of the drive element in the longitudinaldirection thereof are in contact with the wiring member.
 11. The headsuspension assembly of claim 10, wherein one of end portions of thedrive element in the longitudinal direction is fixed to the wiringmember while being partially stacked on the island-shaped portion, andthe other end portion is fixed to the wiring member while beingpartially stacked on the proximal end portion.
 12. The head suspensionassembly of claim 7, wherein the drive element is formed in a curvedshape in accordance with curves of the first curved portion.
 13. A diskdevice comprising: a disk recording medium; and the head suspensionassembly of claim
 7. 14. The disk device of claim 13, wherein the driveelement is provided only at the first curved portion of the bridgeportion.
 15. The disk device of claim 13, wherein the metallic platefurther comprises an island-shaped portion located between the proximalend portion and the support portion and attached to the bridge portionclose to the middle portion.
 16. The disk device of claim 15, whereinthe drive element is attached to the bridge portion such that alongitudinal direction of the drive element is coincident with alongitudinal direction of the bridge portion, and both end portions ofthe drive element in the longitudinal direction thereof are in contactwith the wiring member.
 17. The disk device of claim 16, wherein one ofend portions of the drive element in the longitudinal direction is fixedto the wiring member while being partially stacked on the island-shapedportion, and the other end portion is fixed to the wiring member whilebeing partially stacked on the proximal end portion.
 18. The disk deviceof claim 13, wherein the drive element is formed in a curved shape inaccordance with curves of the first curved portion.